Eh, feels balanced to me so far. I haven't played against many skilled players yet, but enemy assasin demigods havent had too many problems with my minions when I play as Erebus, and I never have issues with enemy minions. I usually just ignore high HP minions and think of them as small DoT spells that are applied to me, which will end when I kill the enemy general, if you keep moving most of them will hardly ever even hit you anyways.
Also, I've been dominating with Erebus against average skilled players, mostly because everyone seems to automatically assume he's a softie. I never burst them until they're at around 1,500 or lower HP, so during a fight they'll assume my DPS is low, and then get suprised when I bite and swarm them, killing them pretty quickly. The bracers that give you +300 damage for ten seconds is pretty helpful as well. Also, luring enemies away from their towers does wonders, occupy your minions with enemy reinforcements, then do standard attacks against an enemy demigod, he'll assume he can kill you easily because your initial DPS is so low... but once you drag him far away enough, pop a HP pot, send all your minions to attack him, bite him and swarm him when he tries to run away. I get a ton of my kills with Erebus simply because other players get cocky and want to get an easy kill.
Anyways... Erebus is the only general I've personally observed to be powerful with minions. QoT just lives a long time, never seen anyone play Sedna online and Oak isn't exactly built for damage. If anything, Erebus is the DPSer of the generals, so expect him to do some decent DPS.